1. Technical Field
The present invention relates to an electronic device that compensates fluctuation of a supply power supplied to a performance circuit, a load fluctuation compensation circuit that compensates fluctuation of a supply power supplied to an electronic device such as a semiconductor circuit, a power supply apparatus provided with the load fluctuation compensation circuit, and a test apparatus provided with the power supply apparatus. More particularly, the present invention relates to an electronic device that compensates a power supply voltage fluctuation caused by a fluctuation in a current consumed by a performance circuit.
2. Related Art
In conventional testing, a supply power for driving is supplied to an electronic device such as a semiconductor circuit, a supply power for driving the electronic device is supplied. For example, a power supply apparatus of a test apparatus supplies the supply power to the electronic device via power supply wiring.
No related Patent Documents or the like are known at present.
In an electronic device such as a CMOS circuit, a consumed current fluctuates according to a fluctuation in operational efficiency of elements included in the electronic device. In such a case, an amount of a voltage drop in a power supply voltage supplied to the circuit of the electronic device fluctuates together with the fluctuation of the consumed current in accordance with an impedance of the power supply wiring connecting the power supply apparatus and the electronic device, the impedance of the power supply wiring inside the electronic device, and an output impedance of the power supply apparatus.
When the fluctuation occurs in the power supply voltage as described above, accurate testing of the electronic device cannot be expected. This type of problem may be solved by preparing a power supply voltage that compensates the fluctuation by detecting the fluctuation of the power supply voltage and feeding the thus detected fluctuation back to the power supply apparatus. For example, when dealing with a DC component of the power supply voltage fluctuation, the power supply voltage supplied to the electronic device can be compensated to be a suitable value by detecting the voltage fluctuation near the power supply input end of the electronic device. Detecting the power supply voltage fluctuation near the power supply input end of the electronic device requires a sense path that branches from the power supply wiring at a location near the power supply input end.
However, because the sense path branches from the power supply wiring, the power supply current partially flows on the sense path. It is necessary to increase the impedance of the sense path to decrease the amount of current flowing to the branch. However, the increase of the impedance of the sense path causes the time constant of the sense path to be undesirably large. Furthermore, it is necessary to provide a large power transistor capable of generating a large power at an output of the power supply apparatus in order to be able to output a large amount of power.
Therefore, it is difficult to have a power supply voltage output that quickly follows the power supply voltage fluctuation near the power supply input end of the electronic device. For example, a low frequency component of the power supply voltage fluctuation can be compensated, but not voltage fluctuation with a period faster than the response speed of the power supply apparatus, which is determined by the size of the power transistor, the time constant of the sense path, and the like.
The fluctuation of the power supply current and of the power supply voltage in relation to the load fluctuation, in other words, load regulation, is especially problematic in semiconductor circuits, which have seen higher integration in recent years, because it leads to noise in peripheral circuits. This leads to the desire for a load fluctuation compensation circuit that can quickly track the power supply voltage fluctuation.